Cheeses are generally made by adding a microorganism to milk which is capable of metabolizing lactose to produce lactic acid and develop acidity. The milk is usually set with a milk clotting or coagulation enzyme, such as rennet, or by developing acidity to the isoelectric point of the casein. Enzyme coagulation of milk also requires an acidic environment. The milk is inoculated with a bacterial culture or starter culture which produces sufficient lactic acid for the rennet to work. The coagulum or curd that results generally incorporates transformed casein, fats including natural butter fat, and flavorings that arise (especially when a bacterial culture is used). The coagulated milk is cut, whey separated and then recovered from the resulting curd. The curd may be pressed to provide a cheese block; curing may take place over a period of time under controlled conditions. For instance, a hard cheese such as cheddar cheese may be cured from about 10 days to one year or more, depending on the desired cheese flavor and body breakdown.
It also is well known to provide a cheese product having some of the characteristics of natural cheese by comminuting one or more natural cheeses, and heating the cheese with an emulsifying agent. The name given to the resulting product depends upon the ingredients used and its composition and, in some instances, is determined by Regulations promulgated by the U.S. Food and Drug Administration, known as Standards of Identity. For example, the term “pasteurized process cheese” refers to a product comprising a blend of cheeses to which an emulsifying agent, and possibly acids, are added, and the mixture is then worked and heated into a homogeneous, plastic mass. Under the current Standards of Identity, the moisture level of process cheese generally does not exceed about 44 percent and process cheese has a minimum fat level of about 40 percent on a dry basis.
It is also known that natural cheese can be manufactured using concentrated milk which has been prepared by membrane processing, such as ultrafiltration, in which milk is cycled across a semi-permeable membrane at an elevated pressure such that water and low molecular weight components pass through the membrane, while certain proteins and fats are retained by the membrane. Cheese making cultures are added to the obtained concentrated milk which is then fermented, usually in the presence of a milk coagulating enzyme, such as rennet, to provide a coagulum. The resulting coagulum is cut or broken to cause syneresis resulting in whey separation. The whey is drained and the curd is processed. The type of cheese cultures used and the processing varies with the desired cheese product. The curd may then be salted, placed in molds, and pressed to allow further whey drainage. The cheese is then ripened to the extent desired.
Cream cheese is an acid-coagulated, non-cured cheese made of dairy components including cream. Cream cheese, which is normally stored under refrigeration conditions, has a smooth and butter-like consistency with a delicate dairy flavor profile, which does not accommodate off-flavors. The texture and body of cream cheese at refrigeration temperatures is generally such that the cream cheese can be sliced and spread. In making cream cheese, sweet cream and dry milk-derived solids or milk are typically blended with a dry blend of vegetable gum and salt in preselected proportions to form a cream cheese mix. The cream cheese mix normally has a butterfat content of from about 10 to about 14 percent (and in certain make procedures up to as much as 20 percent), so that after processing, the finished cream cheese product will have a butterfat content of at least about 33 percent of the product, and a total milk solids content of at least 45 percent corresponding to the presence of not more than about 55 percent moisture in the cream cheese product.
The cream cheese mix is inoculated with a lactic acid culture. Rennet may be used to aid the coagulation of the mix. The mix is cultured by holding it at the inoculation temperature until it has ripened and a coagulum is formed. The acidity of the coagulum may typically be in the range of from about 0.6 to about 0.9 percent (calculated as percent equivalent lactic acid), and the pH of the cultured coagulum may typically be in the range of from about 4.2 to about 5. The resulting coagulum is exposed to a temperature of about 180° F. for a brief period of time and then centrifuged to separate the curd from the whey, and then the cream cheese product is cooled and packaged. Cream cheese generally contains about 2 to about 3 percent lactose.
Lactose (4-O-β-D-galactopyranosyl-D-glucopyranose), commonly called milk sugar, is the primary carbohydrate of milk. Lactose is a low value sugar in food systems because of lactose intolerance and due to its contribution to browning reactions and crystallization. The use of milk substitutes or reduced dairy content in cheese mixes to reduce lactose content in the produced cheese may not provide acceptable products from standpoints of complying with Standards of Identity regulations, processability, and/or ultimate product physical properties and flavor characteristics.
Lactobionic acid (4-O-β-D-galactopyranosyl-D-gluconic acid; CAS Reg. No. 96-82-2) is a water soluble, white crystalline compound and can be synthesized from lactose by oxidation of the free aldehyde group in lactose as carried out catalytically, chemically, electrolytically, or enzymatically. Harju, Bulletin of the IDF 289, ch. 6., pp. 27-30, 1993; Satory et al., Biotechnology Letters 19 (12) 1205-08, 1997. The use of lactobionic acid or its salts as additives in food products previously has been suggested for several specific applications. Calcium or iron chelate forms of lactobionic acid has been described for dietary mineral supplementation. Riviera et al., Amer. J. Clin. Nutr.; 36 (6) 1162-69, 1982. U.S. Pat. No. 5,851,578 describes a clear beverage having a non-gel forming fiber, and water soluble salts of calcium, with or without water soluble vitamins, with or without additional mineral salt supplements and buffered with food acids. The food acid buffering agent includes citric, lactic, maleic, adipic, succinic, acetic, acetic gluconic, lactobionic, ascorbic, pyruvic, and phosphoric acids, as well as combinations thereof. Calcium lactobionate, a salt form of lactobionic acid, has been approved for use as a firming agent in dry pudding mixes. 21 C.F.R. §172.720 (1999). Also, the possible use of lactobionic acid as a general food acidulent has been proposed, albeit without exploration or illustration. Timmermans, Whey: Proceedings of the 2nd Int'l Whey Conf., Int'l Dairy Federation, Chicago, October 1997, pp. 233, 249. This article generally describes lactobionic acid as being useful as an antibiotics carrier, an organ transplant preservative, mineral supplementation, growth promotion of bifidobacteria, or as a co-builder in detergents in its K-lactobionate salt form.
It would be desirable to manufacture cheeses with reduced lactose content while preserving flavor, texture, and appearance characteristics comparable with conventional cheese products. It would also be desirable to reduce starter culturing requirements and the time associated therewith in cheese production, while maintaining acceptable organoleptic attributes. It would also be desirable to increase the solids levels in manufactured cheeses while using reduced amounts of starter cultures as compared to conventional practice. It would also be desirable to be able to use higher lactose containing whey concentrates in cream cheese formulations without the need to increase the usage of cultures. The present invention provides such methods and products in which lactobionic acid is provided in a cheese mix.